Hydropower station construction in Southwest China and Yunnan Province has accelerated noticeably recently owing to the dominant position of hydropower development in China's energy development.But it also has prominent impacts on the ecological environment.Considering the construction features and man made soil and water loss,this article proposes that the“three(water,electricity,and gas) available and one flat(construction site flat)”stage and the time before dam pouring are the cxitical period of s oil and water loss.Dumpling piles and construction roads are the main sources of soil and water loss.Several control mean ures are also proposed,such as proper dumpling pile location,foundation treatment,runoff exhaust,spoil block,spoil platform,and slope management,as well as reasonable water cutoff and drainage on construetion roads,excavated slope stabilization,embankment protection,protection of lower slope,and appropriate vegetation.